#define _GNU_SOURCE
#include "crypto_common.h"
#include <unistd.h>
#include <stdlib.h>

// 增强的S-Box（基于AES但进行了修改）
const unsigned char SBOX[256] = {
    0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
    0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
    0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16
};

// 逆S-Box
const unsigned char INV_SBOX[256] = {
    0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
    0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
    0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
    0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
    0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
    0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
    0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
    0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
    0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
    0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
    0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
    0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
    0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
    0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
    0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
    0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d
};

// 初始化安全随机数生成器
void secure_random_init(void) {
    srand((unsigned int)(time(NULL) ^ (getpid() << 16)));
}

// 生成安全随机数
void generate_secure_random(unsigned char *buffer, size_t length) {
    for (size_t i = 0; i < length; i++) {
        // 使用多重随机源提高随机性
        buffer[i] = (unsigned char)(rand() ^ (rand() >> 8) ^ (time(NULL) + i));
    }
}

// 密钥派生函数
void derive_keys(crypto_context_t *ctx) {
    unsigned char temp[KEY_LENGTH + SALT_LENGTH];
    
    // 组合主密钥和盐值
    memcpy(temp, ctx->primary_key, KEY_LENGTH);
    memcpy(temp + KEY_LENGTH, ctx->salt, SALT_LENGTH);
    
    // 保存原始种子，避免在派生过程中修改
    uint32_t working_seed = ctx->seed;
    
    for (int round = 0; round < ROUNDS; round++) {
        // 每轮使用不同的变换
        for (int i = 0; i < KEY_LENGTH; i++) {
            ctx->derived_keys[round][i] = temp[i % (KEY_LENGTH + SALT_LENGTH)];
            ctx->derived_keys[round][i] ^= (unsigned char)(working_seed >> (8 * (i % 4)));
            ctx->derived_keys[round][i] = SBOX[ctx->derived_keys[round][i]];
            ctx->derived_keys[round][i] ^= (unsigned char)(round * 31 + i * 17);
        }
        
        // 更新工作种子（不修改原始种子）
        working_seed = working_seed * 1103515245 + 12345;
        
        // 暂时移除循环移位，只使用简单的变换
        // rotate_left(ctx->derived_keys[round], KEY_LENGTH, round + 1);
    }
}

// 简化的哈希函数
void hash_function(const unsigned char *input, size_t len, unsigned char *output) {
    uint32_t hash = 5381;
    
    for (size_t i = 0; i < len; i++) {
        hash = ((hash << 5) + hash) + input[i];
    }
    
    // 将32位哈希扩展到更长的输出
    for (int i = 0; i < 32; i++) {
        output[i] = (unsigned char)((hash >> (i % 32)) ^ (hash >> ((i + 16) % 32)));
    }
}

// XOR块加密
void xor_block(unsigned char *data, const unsigned char *key, size_t length) {
    for (size_t i = 0; i < length; i++) {
        data[i] ^= key[i % KEY_LENGTH];
    }
}

// 左循环移位（简化版本 - 字节级）
void rotate_left(unsigned char *data, size_t length, int positions) {
    if (length == 0) return;
    
    // 简化为字节级循环移位，更可靠
    positions = positions % length;
    if (positions == 0) return;
    
    // 使用固定大小的临时缓冲区
    static unsigned char temp[1024];
    if (length > 1024) {
        // 对于超大块，动态分配
        unsigned char *temp_large = malloc(length);
        if (!temp_large) return;
        
        memcpy(temp_large, data, length);
        for (size_t i = 0; i < length; i++) {
            data[(i + positions) % length] = temp_large[i];
        }
        free(temp_large);
        return;
    }
    
    // 复制数据到临时缓冲区
    memcpy(temp, data, length);
    
    // 字节级循环移位
    for (size_t i = 0; i < length; i++) {
        data[(i + positions) % length] = temp[i];
    }
}

// 右循环移位
void rotate_right(unsigned char *data, size_t length, int positions) {
    positions = positions % length;
    if (positions == 0) return;
    
    // 右移等于左移(length-positions)
    rotate_left(data, length, length - positions);
}

// 字节替换
void substitute_bytes(unsigned char *data, size_t length, const unsigned char *sbox) {
    for (size_t i = 0; i < length; i++) {
        data[i] = sbox[data[i]];
    }
}

// 逆字节替换
void inverse_substitute_bytes(unsigned char *data, size_t length, const unsigned char *inv_sbox) {
    for (size_t i = 0; i < length; i++) {
        data[i] = inv_sbox[data[i]];
    }
}

// 高级加密函数
void advanced_encrypt_block(unsigned char *block, size_t block_size, crypto_context_t *ctx) {
    // 多轮加密处理
    for (int round = 0; round < ROUNDS; round++) {
        // 第1步：XOR加密
        xor_block(block, ctx->derived_keys[round], block_size);
        
        // 第2步：字节替换
        substitute_bytes(block, block_size, SBOX);
        
        // 第3步：简单变换（替代循环移位）
        for (size_t i = 0; i < block_size; i++) {
            block[i] = ((block[i] << 1) | (block[i] >> 7)) ^ (unsigned char)(round + 1);
        }
        
        // 第4步：再次XOR（使用不同的密钥片段）
        for (size_t i = 0; i < block_size; i++) {
            block[i] ^= ctx->derived_keys[round][(i + round * 17) % KEY_LENGTH];
        }
        
        // 第5步：复杂变换
        for (size_t i = 0; i < block_size; i++) {
            unsigned char temp = block[i];
            block[i] = ((temp << 3) | (temp >> 5)) ^ (unsigned char)(round * 19 + i * 23);
        }
    }
    
    // 最终混淆
    for (size_t i = 0; i < block_size; i++) {
        block[i] ^= ctx->salt[i % SALT_LENGTH];
    }
}

// 高级解密函数（加密的逆过程）
void advanced_decrypt_block(unsigned char *block, size_t block_size, crypto_context_t *ctx) {
    // 逆向最终混淆
    for (size_t i = 0; i < block_size; i++) {
        block[i] ^= ctx->salt[i % SALT_LENGTH];
    }
    
    // 多轮解密处理（逆向顺序）
    for (int round = ROUNDS - 1; round >= 0; round--) {
        // 逆向第5步：复杂变换
        for (size_t i = 0; i < block_size; i++) {
            // 先逆向XOR
            block[i] ^= (unsigned char)(round * 19 + i * 23);
            // 再逆向位移：左移3变成右移3，右移5变成左移5
            unsigned char temp = block[i];
            block[i] = ((temp >> 3) | (temp << 5));
        }
        
        // 逆向第4步：XOR
        for (size_t i = 0; i < block_size; i++) {
            block[i] ^= ctx->derived_keys[round][(i + round * 17) % KEY_LENGTH];
        }
        
        // 逆向第3步：逆向简单变换
        for (size_t i = 0; i < block_size; i++) {
            block[i] ^= (unsigned char)(round + 1);
            block[i] = ((block[i] >> 1) | (block[i] << 7));
        }
        
        // 逆向第2步：字节替换
        inverse_substitute_bytes(block, block_size, INV_SBOX);
        
        // 逆向第1步：XOR加密
        xor_block(block, ctx->derived_keys[round], block_size);
    }
}